Electric valve circuit



Nov. 5, 1940. D. R. SMITH 2,220,735

ELECTRIC VALVE CIRCUIT Filed April 6, 1939 2 Sheets-Sheet 1 Inventor: Dnalcl R Smith, b9 7 H i S Attorney.

Nov. 5, 1940.

D. R. SMITH ELECTRIC VALVE CIRCUIT lnvefitor:

Donald R. Smith,

MAL

His Attorney.

Patented Nov. 5, 1940 UNITED STATES PATENT OFFICE ELECTRIC VALVE CIRCUITYork Application April 6, 1939, Serial No. 266,398

3 Claims.

My invention relates to electric valve circuits and more particularly tocontrol circuits for electric valve translating apparatus.

In electric valve applications for power pur- 5 poses, it is extremelyimportant in many instances to assure continuity of service by theprovision of additional control or supervisory equipment. For example,in electric valve power equipment for transmitting relatively largequantities of direct current to an associated direct current loadcircuit from an alternating current supply circuit through a pluralityof electric valve means, it is important to maintain at all times asuitable source of control voltage for the electric valve means. Inaddition, where the load is transmitted concurrently by a plurality ofparallel operating electric valve means, it is desirable to maintain apredetermined division or distribution of load among the variouselectric valve means.

In accordance with the teachings described hereinafter, I provide newand improved control circuits whereby a predetermined division of loadmay be maintained among various parallel operating electric valve meansand whereby reliability 5 and continuity of service are assured.

It is an object of my invention to provide a new and improved electricvalve translating circuit.

It is another object of my invention to provide 80 a new and improvedcontrol system for electric valve translating apparatus.

It is a further object of my invention to provide new and improvedcontrol circuits for electric valve means operating in parallel.

35 Briefly described, in the illustrated embodiment of my invention, Iprovide a, new and improved control system for electric valvetranslating apparatus which energizes a direct current load circuit froman associated alternating current supply circuit through a plurality ofelectric valve means operating in parallel. The electric valve means areconnected to transmit current to the load circuit and are of thecontrolled type, each having a plurality of control mem- 45 bers forcontrolling the conductivities of the associated arc discharge paths.Each of the electric valve means is provided with an excitation circuitwhich impresses on the control members suitable control voltages todetermine or control the 50 amount of current conducted by that electricvalve means. Each of the excitation circuits comprises a control deviceor phase shifting device Which impresses on the control members suitablevoltagesto control the output of the 55 electric valve means. A mastercontrol device or master phase shifter controls the excitation circuitssimultaneously to effect control of the output of the electric valvemeans. As a means for assuring continuity of service, I provide aplurality of control circuits for energizing the 5 excitation circuitsand I also provide a means for effecting selective energization of theexcitation circuits from the control circuits, so that in the event offailure of one of the control circuits energization of the excitationcircuits may be 10 efiected from another control circuit.

For a. better understanding of my invention, reference may be had to thefollowing description taken in connection with the accompanyingdrawings, and its scope will be pointed out in the 15 appended claims.Figs. 1 and 2, considered conjointly, represent an embodiment of myinvention as applied to a twenty-four phase electric valvetranslatingcircuit for transmitting power between a three phasealternating current supply 20 circuit and a direct current load circuit.

Considering Figs. 1 and 2 conjointly, my invention is therediagrammatically illustrated as applied to an electric valve translatingsystem for transmitting power between an alternating current circuit Iand a direct current circuit comprising conductors 2 and 3. For thepurposes of illustration, my invention is shown as applied to atwenty-four phase system for transmitting power between the alternatingcurrent circuit and the direct current circuit. The electric valvetranslating system comprises a plurality of electric valve means 4-|lwhich are energized by transformers I2, [3, l4 and I5. Electric valvemeans 4 and 5 are energized by transformer I2, and electric valve means6 and 1 are energized by transformer l3. In like manner, electric valvemeans 8, 9 and I0, II are energized by transformers or transformer banksl4 and I 5 (not shown). The transformers may be connected in 4b themanner disclosed and claimed in a copending patent application ofEverett F. Christensen, Serial No. 235,628, filed October 18, 1938, andassigned to the assignee of the present application. Transformer l2comprises delta-connected primary windings l6 and groups of secondarywindings 11-20. In order to control the voltage impressed on the primarywindings I6 of transformer I2, I may employ any suitable arrangementsuch as an auto-transformer 2| having a plurality of windings 22 and anadjustable contact means 23. Transformer l3, which energizes electricvalve means 6 and 1, comprises two groups of primary windings 24 and 25,the former of which is delta-connected and the latter of which isstar-connected. The transformer l3 also has a plurality of groups ofsecondary windings 26-29, inclusive. A voltage controlling means, suchas an auto-transformer 38, may be employed to control the voltagesimpressed on primary windings 2 and 25 of transformer 13. Thetransformers or transformer banks i l and !5 (not illustrated) aresimilar in construction and arrangement to transformers l2 and i3,respectively. Interphase transformers 3! and 32 are connected betweensecondary windings ll, 58 and I9, 20 respectively of transformer 12, andinterphase transformer 33 is connected to interphase transfomers 3! and32 so that the secondary windings and associated electric valve means 4and 5 operate as a twelve phase arrangement. In like manner, theinterphase transformers 36, 35 and 36 are associated with secondarywindings 26-29 of transformer 53 and also, in turn, operate as a twelvephase system displaced in phase with respect to the secondary voltagesof transformer !2. The two twelve pha e systems are interconnected bymeans of an interphase transformer 37, so that the resultant ripplecorresponds to a twenty-four phase system. All of the interphasetransformers of the transformer banks I4 and i5 are not shown. However,interphase transformers 38, 35 and all are shown corresponding infunction to interphase transformers 33, 36 and 31.

Suitable circuit controlling means, such as contactors or switchesll-55, may be connected between transformer banks 52-45, respectively. Asuitable isolating switch 35 may be connected between the two parts ofthe system, that is, between electric valve means i'!and 8lrespectively.

The electric valve means d-l! are preferably of the type employing anionizable medium, such as a gas or a vapor, and each may include aplurality of anodes G6, a self-reconstructing cathode such as a mercurypool cathode ll, and a plurality of control members 8 which control theconductivities of the associated arc discharge paths. The electric valvemeans i!.! may each be provided with a plurality of holding or aremaintaining anodes 49.

The holding anodes is of the electric valve means 4!! may be energizedfrom a plurality of circuits 5il5'!, respectively. Each of the circuits50-51, respectively, may comprise a suitable transformer 58 havingprimary windings 59 and secondary windings 50 for energizing the holdinganodes 49. The circuits 5ll5l in turn may be energized from a pluralityof control circuits 5! and 62. Circuit 5! may be energized from thealternating current circuit l through a switching means or contactor 63and a transformer 64,-and control circuit 62 may be energized fromcircuit 1 through a switching means 65 and a transformer 65. Undernormal operating conditions circuits till-53 are energized from controlcircuit 6! through switch 67!, and circuits 54-5'! are energized fromcontrol circuit 52 through switch 68. Switches 6'! and 68 are providedwith operating coils 65 and Hi, respectively, and are also provided withauxiliary contacts H, H0. and 72, 12a. An interconnecting switch 13 isprovided to connect circuits 5ll53 and 545! in the event either ofcontrol circuits 6! or 62 becomes defective or inoperative, so that allof the holding anodes of the electric valve means 4! I may be energizedto assure continuity of service. Switch 13 is provided with an actuatingcoil 14 which is connected to a, control circuit 15 which in turn isenergized from a battery it through the auxiliary contacts H and T2 ofswitches 6! and 58. A suitable circuit controlling means, such as aswitch ll, may be employed to interrupt circuit 75 to open switch 73.

Actuating coils 65 and ill of switches ii! and 55 are connected to beresponsive to a predetermined electrical condition of control circuits6! and 62, respectively. When the predetermined electrical condition issatisfied, as, for example, when the circuits 5! and 62 are in conditionfor satisfactory operation, coils 59 and iii are energized from circuits5! and 52 through auxiliary contacts lid and 72a, respectively. In theevent the voltage of either one of these circuits fails, the associatedcoil 55 or F5 is deenergized and the switch drops to the open circuitposition.

electric valve means 4 and 5 havebeen shown in detail. The excitationcircuits '!8 and 19 each comprise a control device which may be phaseshifting devices 86 and 81, respectively. The phase shifting devices maybe of the rotary phase shifting type having distributed primary windings88 and secondary windings 89. Of course, the phase shifters 86 and 8!maybe of the type including controllable or adjustable static impedanceelements, such as combinations of resistances, inductances orcapacitances. The phase shifters and 8i may also be of the adjustable orcontrollable type to control the phase of the voltage impressed oncontrol members 18 with respect to the voltages of the associatedanodes. The excitation circuits '!885 are connected to be energized froma master phase shifting device 99 which, in turn, is connected to beenergized from a suitable source of alternating current, such as circuitthrough control circuits 9! and 92. A switch 93 may be connected betweenexcitation circuits 'l885 and the master phase shifter 90, and a switch94 may be connected between the master phase shifter and circuits 9! and92 to disconnect or connect the master phase shifter 59 to excitationcircuits 18-85. Switches or contacts 95 and 95 are connected in controlcircuits 9! and 92, respectively, to permit energization of theexcitation circuits 'l8-85 from either or both of these controlcircuits. Switches 95 and 96 may be arranged to be maintained normallyin the closed circuit position so that the excitation circuits areenergized from both circuits 9! and 92, and in the event one of thecontrol circuits becomes defective or inoperative the associated switchmay be opened so that the excitation circuits are neverthelessenergized, thereby assuring continuity of control voltage. For example,switch 95 may be provided with an actuating coil 95a and a pair ofauxiliary contacts 962; to maintain the switch 95 closed so long as thevoltage of the control circuit 92 is in satisfactory operatingcondition. However, when the voltage of circuit 9?. fails, coil 96abecomes deenergized and opens switch 35. A similar operating mechanismmay be associated with switch 95. Switches 55 and 95 may be arranged sothat the excitation circuits are normally energized from only one of thecontrol circuits 9! and 92, in which case in the event the operatingcontrol circuit becomes defective, switches 95 and 96 are actuated todisconnect the defective control circuit and connect the excitationcircuits to the other control circuit. If it is desired to energize theexcitation circuits from only one of control circuits 9| and 92 duringnormal operating conditions and to effect a transfer of control from thedefective circuit to the circuit in operating condition, a controlcircuit and interlocking mechanism similar to control circuit I5 andcontacts II and I2 of switches 67 and 68 may be employed. Controlcircuits 9| and 92 may be energized from an alternating current circuitof suitable phase and frequency, such as the alternating current circuitI, through transformers 9! and 98, respectively. Suitable currentlimiting or protective devices, such as fuses 99, may be employed ifdesired.

As a means for controlling the conductivities of all of the electricvalve means 4II in response to a predetermined controlling influence andat the same timemaintaining a predetermined distribution of load amongthe various electric valve means, I provide a control circuit I00. Thecontrol circuit I00 may be responsive to a predetermined electricalcondition of the system, such as the voltage of the alternating currentcircuit I, and may comprise a regulator IOI. A positioning motor I02 maybe mechanically coupled to the master phase shifter 90. The motor I02may have a pair of field windings I03 and I04, the energization of whichis controlled by contacts I05 of regulator IUI. A switch I06 may be usedto connect the regulator IOI operatively in the circuit or to effectmanual control or positioning of the motor I02.

Switches or contactors IOI-I I4 are connected between the conductor 3and the cathodes 4-'I of electric valve means 4I I, respectively. As ameans for producing a negative unidirectional biasing potential which isimpressed on the control members 48 of electric valve means 4II throughthe secondary windings of transformer banks I 2I5, I provide anysuitable arrangement, such as direct current generators H5 and IIIS,which in the drawing are shown as being associated with electric valvemeans 4 and 5. It is to be understood that corresponding generators (notshown) are associated with the electric valve means 6-I I. Thegenerators II 5 and H6 may be driven by any suitable motor, such as analternating current motor III, energized from either control circuit 6|or 62. Generators H5 and II 6 produce unidirectional voltages across theterminals of resistances H8 and I I9 which are connected in the controlcircuits for control members 48.

The operation of the embodiment of my invention diagrammaticallyillustrated in Figs. 1 and 2 will be explained by considering the systemwhen it is operating as a double twenty-four phase system for supplyingunidirectional cur rent to the direct current circuit comprisingconductors 2 and 3 from the alternating current circuit I. Electricvalve means 4-! operate as a twenty-four phase rectifier and electricvalve means 8---! I also operate as a twenty-four phase rectifier. Themanner in which these rectifiers operate is more fully explained in theabove identified copending patent application of Everett F. Christensen,Serial No. 235,628.

The distribution of load among the various electric valve means iseffected by the adjustment of the rotary phase shifters in the variousexcitation circuits, of which rotary phase shifters 86 and 81 ofexcitation circuits I8 and I9 are exemplary. When switch 93 is in theclosed circuit position and when switch 94 is in the lefthand position,the conductivities of the electric valve means 4II are controlled bymeans of the control or regulating circuit I00 through the master phaseshifter 90. When switch I06 is in the position shown, regulator I 0|controls the energization of field windings I03 and I04 to position themaster phase shifter in response to the voltage of circuit I. If it isdesired to maintain the output voltage at a substantially constantvalue, the input Voltage of circuit I may .be employed to adjust thephase of the voltages impressed on control members 48 in response to thevariations in voltage of circuit I. Of course, it is to be understoodthat the regulator I 0| may be connected to be responsive to the voltageor current of the direct current load circuit including conductors 2 and3.

Under normal operating conditions circuits 50-53 and 54--5I areenergized from control circuits GI and 62, respectively. Actuating coils69 and I0 of switches 61 and 68 may be energized from circuits GI and 62and maintained in the closed circuit position so long as circuits BI and62 operate in a satisfactory manner. However, in the event one of thecircuits fails, the associated switch will open effecting energizationof control circuits I5 and consequently closing switch I3 by theenergization of coil I4 thereof, in this manner assuring energization ofall of circuits 505I in the event of failure of one of the associatedcontrol or supply circuits.

Energization of excitation circuits I885 is assured inasmuch as theseexcitation circuits are energized normally from either or both controlcircuits 9| and 92 through switches and 96. However, it is to beunderstood that in the event either control circuit 9| or 92 becomesdefective or inoperative, the associated switch may be operatedautomatically in response to that condition to disconnect the defectivecontrol circuit and to effect energization of the excitation circuitsfrom the other control circuit.

While I have shown and described my invention as applied to a particularsystem of connections and as embodying various devices diagrammaticallyshown, it will be obvious to those skilled in the art that changes andmodifications may be made without departing from my invention, and I,therefore, aim in the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. In combination, an alternating current circuit, a direct currentcircuit, a plurality of electric translating circuits connected betweensaid first mentioned circuits and each including electric valve meanshaving control members for controlling the conductivity thereof, aplurality of excitation circuits each associated with a different one ofsaid electric valve means and each comprising a phase shifting devicefor adjusting the phase of the voltages impressed on the associatedcontrol members with respect to the voltage of said alternating currentcircuit, a plurality of control circuits energized from said alternatingcurrent circuit, a master phase shifting means for energizing the phaseshifting devices to effect simultaneous control of the voltagesimpressed on said control members, and

means for selectively energizing said master phase shifter vfrom saidcontrol circuits.

2. In combination, an alternating current circuit, a direct currentcircuit, a plurality of electric translating circuits connected betweensaid first mentioned circuits and each including electric valve meanshaving control members for controlling the conductivity thereof, aplurality of excitation circuits each associated With a different one ofsaid electric valve means and each comprising a phase shifting devicefor adjusting the phase of the voltages impressed on the associatedcontrol members with respect to the voltages of said alternating currentcircuit, a plurality of control circuits energized from said alternatingcurrent circuit, a master phase shifting means for energizing the phaseshifting devices to efiect simultaneous control of the voltagesimpressed on said control members, meansfor selectively energizing saidmaster phase shifter from a predetermined one of said control circuits,and. means for positioning said master

